<template>
    <div class="header">
        <router-link
            tag="div"
            to="/"
            class="header-abs"
            v-show="showAbs"
        >
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div
            class="header-fixed"
            v-show="!showAbs"
            :style="opacityStyle"
        >
            景点详情
            <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
        </div>
    </div>
</template>
<script>
export default {
    name: 'DetailHeader',
    data () {
        return {
            showAbs: true,
            opacityStyle: {
                opacity: 0
            }
        }
    },
    methods: {
        handleScroll () {
            const top = document.documentElement.scrollTop
            if (top > 60) {
                let opacity = top / 140
                opacity = opacity > 1 ? 1 : opacity
                this.opacityStyle = {
                    opacity
                }
                this.showAbs = false
            } else {
                this.showAbs = true
            }
        }
    },
    activated () {
        window.addEventListener('scroll', this.handleScroll)
    },
    deactivated () {
        window.removeEventListener('scroll', this.handleScroll)
    }
}
</script>
<style lang="stylus" scoped>
@import '~styles/varibles.styl'
.header-abs
    position absolute
    left 0.2rem
    top 0.2rem
    width 0.8rem
    height 0.8rem
    line-height 0.8rem
    border-radius 0.4rem
    text-align center
    background rgba(0, 0, 0, 0.8)
    .header-abs-back
        color #ffffff
        font-size 0.4rem
.header-fixed
    z-index 2
    position fixed
    top 0
    left 0
    right 0
    overflow hidden
    height $headerHeight
    line-height $headerHeight
    text-align center
    color #fff
    background $bgColor
    font-size 0.32rem
    .header-fixed-back
        width 0.64rem
        text-align center
        font-size 0.4rem
        position absolute
        top 0
        left 0
        color #fff
</style>
